47 research outputs found

    Environmental impacts of cement production. A statistical analysis

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    The attention to environmental impacts of cement production has grown fast in recent decades. The cement industry is a significant greenhouse gases emitter mainly due to the calcinations of raw materials and the combustions of fuels. This paper investigates on the environmental performances of cement production and on the identification of factors driving emissions. For this purpose, a sample of 193 different recipes of gray cement produced in Italy from 2014 to 2019 according to the European standard EN 197-1. This paper identifies the consumption impact categories (e.g., fossil fuels, renewable and non-renewable secondary fuels) that explain the assessment of the Global Warming Potential, one of the most crucial impacts of cement production. Having regard to the overall examined dataset and each cement type, a set of predictive models is implemented and evaluated. A similar approach has been adopted to produce accurate predictive models for further environmental impact categories that quantify emissions to air. The obtained results provide important information that can support cement producers to develop low-impacting cement recipes

    Spreading equilibria under mildly singular potentials: pancakes versus droplets

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    We study global minimizers of a functional modeling the free energy of thin liquid layers over a solid substrate under the combined effect of surface, gravitational, and intermolecular potentials. When the latter ones have a mild repulsive singularity at short ranges, global minimizers are compactly supported and display a microscopic contact angle of π/ 2. Depending on the form of the potential, the macroscopic shape can either be droplet-like or pancake-like, with a transition profile between the two at zero spreading coefficient for purely repulsive potentials. These results generalize, complete, and give mathematical rigor to de Gennes’ formal discussion of spreading equilibria. Uniqueness and non-uniqueness phenomena are also discussed

    Shape programming of a magnetic elastica

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    We consider a cantilever beam which possesses a possibly non-uniform permanent magnetization, and whose shape is controlled by an applied magnetic field. We model the beam as a plane elastic curve and we suppose that the magnetic field acts upon the beam by means of a distributed couple that pulls the magnetization towards its direction. Given a list of target shapes, we look for a design of the magnetization profile and for a list of controls such that the shapes assumed by the beam when acted upon by the controls are as close as possible to the targets, in an averaged sense. To this effect, we formulate and solve an optimal design and control problem leading to the minimization of a functional which we study by both direct and indirect methods. In particular, we prove that minimizers exist, solve the associated Lagrange-multiplier formulation (besides non-generic cases), and are unique at least for sufficiently low intensities of the controlling magnetic fields. To achieve the latter result, we use two nested fixed-point arguments relying on the Lagrange-multiplier formulation of the problem, a method which also suggests a numerical scheme. Various relevant open question are also discussed

    Accessible opera : overcoming linguistic and sensorial barriers

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    The desire to make media available for all has been rapidly accepted and implemented by most European countries. Opera, as one of the many audiovisual representations, also falls under the category of production which needs to be made accessible and this article aims to analyse how opera has gone through a complete transformation to become a cultural event for all, overcoming not only linguistic but also sensorial barriers. The first part of the article analyses the various forms of translation associated with opera and the main challenges they entail. The second presents different systems used to make opera accessible to the sensorially challenged, highlighting their main difficulties. Examples from research carried out at the Barcelona's Liceu opera house are presented to illustrate various modalities, especially audio description. All in all, it is our aim to show how translated-related processes have made it possible to open opera to a wider audience despite some initial reluctance

    Existence and uniqueness results for possibly singular nonlinear elliptic equations with measure data

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    We study existence and uniqueness of solutions to a nonlinear elliptic boundary value problem with a general, and possibly singular, lower order term, whose model is {-Δpu=H(u)μinΩ,u>0inΩ,u=0on∂Ω.Here Ω is an open bounded subset of RN (N≥ 2), Δ pu: = div (| ∇ u| p-2∇ u) (1 < p< N) is the p-laplacian operator, μ is a nonnegative bounded Radon measure on Ω and H(s) is a continuous, positive and finite function outside the origin which grows at most as s-γ, with γ≥ 0 , near zero
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